Question

need answer fast please​

Answer 1

Explanation:

for any 2 vectors

a,b

the dot product when the angle beteween them is 90° is 0

a.b=|a|×|b|×cos(ø)

in this case ø=90

cos(90)=0

hence

a.b=0

similarly for orthogonal unit vectors

i.i=j.j=k.k=1

and

i.j=j.k=k.i=0